Up to 60 Irish veterans of World War One who were buried in four communal graves will be honoured at Deansgrange cemetery in Dublin.
The men were buried over several decades but only their names and the dates of their deaths are inscribed on the four gravestones.
For the first time, their wartime service will be acknowledged at a ceremony during which four new granite plaques will be unveiled.
Inscriptions in both English and Irish will say: "Dedicated to the memory of the men buried here who served in The Great War 1914-18."
The ceremony will take place on Sunday, September 21, at 2pm and will be hosted by the Cathaoirleach of Dun Laoghaire-Rathdown County Council, Marie Baker.
Representatives of the Friends of The Somme Association will travel from the North.
Military historian Liam Dodd (62), said: "These plots were provided by Leopardstown Park Hospital which had cared for Irish war veterans for many decades.
"Much of the funding for their care would have been provided by the British authorities who also assisted in the burials of those Irish veterans who may not have had immediate family when they died in old age.
"We don't know many details about the men buried here. We'd love to hear from any relatives to learn more about them."
A list of the names is available on the website royaldublinfusiliers.com. Up to 60 of the 62 men buried in the plots served in the war, it is believed.